• Journal of Korean Society of Steel Construction
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• v.24 no.6
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• pp.659-670
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• 2012

The purpose of this study is to formulate the local displacement and moments of a plate stiffened with open ribs according to the dimensions of stiffened plates. Analyzed results of various plates stiffened with rectangular and reverse T ribs show that the effect of the lower flange to the local behavior is very small, so the local behavior can be expressed by ratio functions of the rib space, web thickness, web height and plate thickness and the ratio functions of rectangular and reverse T ribs can be unioned. The application of ratio functions to other types of stiffened plates shows that the increment of the error ratio is so small compared with examples of this study that the applicability of this study is proved.

• Journal of Korean Society of Steel Construction
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• v.26 no.4
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• pp.277-288
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• 2014

In this study, the local displacement and moment characteristics of a plate stiffened with closed ribs are analyzed according to the dimensions of stiffened plates. The analyzed results of various stiffened plates under square distributed load show that the effect of the loading panel width to the local behavior is dominant but that of the next panel width is very small. And the local behavior of reference stiffened plates can be expressed by the angle between the plate and the rib, and that of other stiffened plates can be obtained by multiplying ratio functions of the loading panel width, plate thickness, rib thickness, rib height and next panel width and they give good results. Applying ratio functions to other loading sizes shows that the applicability of ratio functions except for the loading panel width is proved and the modified ratio functions of the loading panel width improve error ratios. Therefore, the local displacement and moments of a plate stiffened with closed ribs can easily achieve proper results regardless of the dimensions using ratio functions proposed in this study.

• Journal of Korean Society of Steel Construction
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• v.19 no.2
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• pp.161-170
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• 2007

In this study, to improve on the inaccurate results of the orthotropic plate analysis, we aim to propose a modified coefficient of the orthotropic flexural rigidity for stiffened plates with rectangular ribs considering the dimensions of ribs. The sensitivity of the flexural rigidity and the maximum displacement according to the dimensions of stiffened plates were analyzed and the parametric study on the modified coefficient of the orthotropic flexural rigidity of stiffened plates was performed. The results show that the ratio of modified coefficients can be expressed as a function for each rib height, space and thickness regardless of plate thickness and the modified flexural rigidity can be easily estimated from the ratio functions of modified coefficients. The application of the coefficient function to various types of stiffened plates with different boundary conditions, aspect ratios, rib arrangement and loading size shows that the proposed function improves the accuracy of the orthotropic plate analysis compared with the results of the reference. Therefore, the orthotropic plate analysis of stiffened plates with rectangular ribs can easily achieve more accurate results using the coefficient function proposed in this study.

• Journal of Korean Society of Steel Construction
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• v.25 no.3
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• pp.267-278
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• 2013

In this study, stiffened plates with open ribs are analyzed to estimate and formulate the local displacement and local moments according to square loading sizes. For the local behaviors of plates stiffened with rectangular and reverse T ribs, the ratio functions according to the dimensions of stiffened plates are obtained at each square loading size. Analytical results show that values of the basic stiffened plates are different but the ratio functions of each square loading size are similar and the difference of the ratio functions between rectangular ribs and reverse T ribs are small, so the ratio functions can be unified by integrating the loading sizes regardless of the rib type. The application of the unioned ratio functions to L type ribs and rectangular loading shows good accuracies. Therefore, the local behaviors of plates stiffened with open ribs can easily be obtained by using the unioned ratio functions proposed in this study.

• Journal of Korean Society of Steel Construction
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• v.30 no.1
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• pp.59-66
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• 2018

In this study, the parametric analysis for the buckling behavior of plates stiffened with the new type(${\Box}$ type) ribs was performed. Changes of the buckling capacity according to dimensions of ${\Box}$ type ribs show certain behaviors, so that the system to find the section of ${\Box}$ type ribs under the specific buckling capacity can be proposed. Applying this system to the steel deck of existing bridges, more economic sections of ${\Box}$ type ribs rather than that of closed ribs can be obtained. Therefore, the economic section of steel deck having the required buckling capacity can be designed by using the proposed system of ${\Box}$ type ribs.

• Journal of the Korean Society for Advanced Composite Structures
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• v.3 no.1
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• pp.29-34
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• 2012

Even though the longitudinally stiffened laminated composite plates with closed section ribs should be an effective system for axially compressed members, the existing researches on the applications of closed-section ribs, especially for the laminated composite plates, are not sufficient. This study is aimed to examine the influence of the sectional stiffness of U-shaped ribs on the buckling modes and strengths of laminated composite plates. Applying the orthotropic plates with eight layers of the layup $[(0^{\circ})_4]_s$ and $[(0^{\circ}/90^{\circ})_2]_s$, 3-dimensional finite element models for the U-rib stiffened plates were setup by using ABAQUS and then a series of eigenvalue analyses were conducted. From the parametric studies, the minimum required ply thicknesses as well as the buckling strengths were presented for the analysis models. The buckling strengths were compared with the theoretical critical stress equation for simply supported plates based on the Classical laminated plate theory. This study will contribute to the future study for evaluating the minimum required stiffness and optimum design of U-rib stiffened plates.

• Journal of Korean Society of Steel Construction
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• v.19 no.6
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• pp.621-632
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• 2007

The purpose of this study was the estimation and formulation of orthotropic flexural rigidities considering the deformed shape for a plate stiffened with rectangular ribs. Analytical results of methods modifying the flexural rigidity of the x-direction, the y-direction or both directions were compared at the center, the x-directional quarter point and the y-directional quarter point of stiffened plates loaded at the center. The composite method modifying the flexural rigidity of both directions improves the accuracy compared with the other methods. Moreover, the ratio of modified coefficients for each directional rigidity can be expressed as a function corresponding to each dimension of stiffened plates. The application of modified coefficient functions to various types of stiffened plates with different boundary conditions, aspect ratios and rib arrangement shows that the increment of the error ratio is small compared with examples of this study and the application of proposed functions shows more accurate results than previous methods modifying the flexural rigidity. Therefore, by using the modified coefficient functions proposed in this study, the orthotropic plate analysis of plates stiffened with rectangular ribs can easily achieve more accurate displacement results.

• Journal of Korean Society of Steel Construction
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• v.16 no.2 s.69
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• pp.191-200
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• 2004

In this paper, the modified method of orthotropic rigidities for stiffened plates with open ribs is proposed to solve the problem of the inaccurate results of the orthotropic plate analysis according to the dimensions of stiffened plates. In analyzing various types of stiffened plates with open ribs using the isotropic and orthotropic plate element, orthotropic plates are found to gave smaller maximum displacements compared to isotropic plates in a range that is smaller than the special rigidity ratio and reversely. Therefore, obtaining a more accurate solution of the orthotropic plate analysis requires modifying the orthotropic rigidities of stiffened plates according to the rigidity ratio. This study presents two modified methods using the displacement function and the displacement ratio. The application of the two methods improves the accuracy of the results of the orthotropic plate analysis, although the modified method using the displacement ratio is better than the method using the displacement function in terms of serviceability and safety. The comparison with the experimental example shows that the proposed modified method improves accuracy. Therefore, the orthotropic plate analysis of stiffened plates with open ribs can achieve more accurate results using the proposed method in this study.

• Journal of Korean Society of Steel Construction
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• v.20 no.4
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• pp.455-467
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• 2008

The dynamic vehicle running tests were performed to analyze dynamic behavioral characteristics such as displacement, strain history loop and vibration acceleration in arch bridges. Also, the validity of the modeling was verified by comparing the results of the tests and those of the structural analysis modeling. With the resonance revision of verified modeling, when the ratio of excited frequencies to natural frequencies exceeds ${1{\pm}0.04}$, the stability of the bridge is obtained. Also, in the event of resonance by speed parameter, the second mode shape is dominant to the dynamic behaviors of arch bridges. It is found that manipulating the parameters involving arch ribs can increase the second mode natural frequency. It makes critical velocity greater than operational velocities to guarantee the stability of arch bridges.

• Journal of the Korea Concrete Institute
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• v.18 no.5 s.95
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• pp.579-588
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• 2006

In recent years, the availability of high-strength reinforcing and prestressing steels leads us to build economically and efficiently designed concrete structural members. One of critical problems faced to the structural engineers dealing with these types of structural member is controls of crack width that is used as a criterion for the serviceability in the limit state design. Especially, flexural cracking must be controlled to secure the structural safety and to improve the durability as well as serviceability of the load carving members. The proposed method utilizes the results of pure tension test in which tensile loads are applied both side of specimen, done by Ikki. The bond characteristics of deformed reinforcing bar under pure tension is considered by the area of concrete and rib area. The results of proposed method are compared with the test data and the results show that the proposed method can take into account the dimensions, variation of sectional properties, and direction of reinforcing and gives more accurate maximum bond stress and corresponding relative slip than the existing methods. the characteristics of bonding is considered by using dimensionless slip magnitude and effective reinforcement ratio. The validity of the proposed equation is verified by test experimental data.